Effect of Hydrocarbon Concentration on Particulate Deposition and Microstructure of the Deposit in Exhaust Gas Recirculation Cooler

An original nondestructive sampling method to study the effect of gravity on the deposition of micron-sized large particles in exhaust gas recirculation (EGR) cooler fouling

“…31,39,40 Figure 4(a) shows the interface between fouling and the metal tube wall in the cross-section for a sample obtained by a common sampling method. 26 The interface is unclear at the microscopic level in this way. This is because the cutting process of the sampling tube damages the fouling, and the irregular extension of the metal creates rolled edges that obstruct the observation of the fouling.…”

“…(a) 500× cross-sectional SEM image of fouling under the typical sampling method. 26 (b) 500× cross-sectional SEM image of fouling under the sampling method proposed in this paper.…”

“…Past studies have identified condensation 21,25,26,33 and thermophoresis 34,35 as essential effects contributing to fouling, while the contribution of gravity is minimal, 35 but this is a result of studies considering the nano-particulate matter, and there is a lack of studies on the deposition process of large particles at the micron level in EGR coolers. More importantly, past studies on gravitational effects in EGR cooler fouling have usually been numerical simulation approaches, lacking actual and quantitative experimental data.…”

“…The hydrocarbon condensation and its effect on the fouling has particularly attracted the attention of many researchers recently, leading to numerous works on this subject. [18][19][20][21][22][23] Our previous works on hydrocarbon condensation 9,[24][25][26] have shed light on the mechanisms and effects of condensation to some extent. However, some findings are still poorly explained, for example, large particles at the micron level were found in the EGR cooler, 2,[27][28][29][30][31][32] which differs from the typical nanoscale particulate matter in the exhaust gas.…”